Academic literature on the topic 'Dissertations – Forest and wood science'

The Tambopata region of the southern Peruvian Amazon supports a high diversity of both woody plants and forest types. Woods collected from low riverside vegetation, floodplain forest, clay-soil forest on an upper terrace, sandy-soil forest, and swamp forest provide an opportunity to test for significant differences in quantitative anatomical characters among forest types. Vessel-element length in floodplain-forest trees is significantly greater than in the other forest types. Specific gravity is lower in the two early-successional associations (low riverine forest and mature floodplain forest). Vessel diameter and density do not show significant differences among forest types and may be responding to overall climate controls. These two characters, however, show a pattern of variation within a transect extending back from the river along a gradient of increasing substrate and forest age; in addition, sites characterized by frequent flooding or presence of standing water lack vessels in the wider-diameter classes. The six characters analyzed show distributions that are, with the exception of wood specific gravity, significantly nonnormally distributed, a consideration that may be important in representing characteristics of assemblages of taxa. The degree of variability seen in some of the quantitative characters shows the importance of either basing analysis on adequate sample sizes or identifying robust indicators that can be used with small samples.

Wood samples were taken from the upper and lower sides of 21 naturally tilted trees from 18 families of angiosperms in the tropical rain forest in French Guyana. The measurement of growth stresses ensured that the two samples were taken from wood tissues in a different mechanical state: highly tensile stressed wood on the upper side, called tension wood, and lower tensile stressed wood on the lower side, called opposite wood. Eight species had tension wood fibres with a distinct gelatinous layer (G-layer). The distribution of gelatinous fibres varied from species to species. One of the species, Casearia javitensis (Flacourtiaceae), showed a peculiar multilayered secondary wall in its reaction wood. Comparison between the stress level and the occurrence of the G-layer indicates that the G-layer is not a key factor in the production of high tensile stressed wood.

The anatomy of tension wood and opposite wood was compared in 21 tropical rain forest trees from 21 species belonging to 18 families from French Guyana. Wood specimens were taken from the upper and lower sides of naturally tilted trees. Measurement of the growth stress level ensured that the two samples were taken from wood tissues in a different mechanical state: highly tensile-stressed wood on the upper side, called tension wood and normally tensile-stressed wood on the lower side, called opposite wood. Quantitative parameters relating to fibres and vessels were measured on transverse sections of both tension and opposite wood to check if certain criteria can easily discriminate the two kinds of wood. We observed a decrease in the frequency of vessels in the tension wood in all the trees studied. Other criteria concerning shape and surface area of the vessels, fibre diameter or cell wall thickness did not reveal any general trend. At the ultrastructural level, we observed that the microfibril angle in the tension wood sample was lower than in opposite wood in all the trees except one (Licania membranacea).

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2009.
ENGLISH ABSTRACT: Wood waste, when used for gasification is commonly pressed into briquettes, especially if no uniform particle size is available. This densification reduces problems of handling, storage and transportation and improves the combustion performance because of a more uniform fuel size. Briquettes have to be mechanically strong enough to be handled. Cohesive strength is provided by residual moisture and lignin present in the wood. The lignin acts as a natural binder. However, the briquetting process becomes more complicated if one wants to add other agricultural waste products that do not necessarily contain lignin as binders,, In this study we have investigated various briquetting process parameters, such as mixing ratios of briquettes containing wood chips, grape skins and chicken litter, moisture content and press time. The aim was to determine the optimum process parameters that allow the production of briquettes, containing a blend of biomaterials that are mechanically stable to allow further handling but yield high energy content at the same time.
AFRIKAANSE OPSOMMING: Wanneer houtafval vir vergassing gebruik word en die partikelgrootte daarvan varieer, word die materiaal normaalweg in ’n brikket gedruk. Brikketvorming vergemaklik opberging, hantering en vervoer. Weens die meer uniforme grootte en vorm van die brikkette is verbranding daarvan heelwat meer doeltreffend. Brikkette moet egter meganies sterk genoeg wees om hanteer te kan word. Die kohesiewe sterkte word deur residuele vog en lignien, wat as natuurlike bindmiddel in hout aanwesig is, verskaf. Indien ander materiale soos landbouafval, wat noodwendig geen lignien bevat nie egter gebruik word, word die brikketvormingsproses meer kompleks. In hierdie ondersoek is verskeie brikketvormingsparameters evalueer. Mengverhoudings van brikkette wat houtspaanders, druiwedoppe en hoendermis bevat, asook invloed van materiaalvoggehalte en druktyd is bestudeer. Die doel was om die optimale materiaal- en prosesparameters vas te stel wanneer ’n mengsel van biomateriale gebruik word om brikkette te lewer wat meganies sterk genoeg is maar steeds die hoogste energieopbrengs lewer.
Centre for Renewable and Sustainable Energy Studies

Thesis (PhD(For))--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Pinus patula is the most intensively planted conifer in the tropics and sub‐tropics. In South Africa Pinus patula plantations are the main saw‐log resource for structural lumber production. Improved intensive silvicultural practices and tree breeding have resulted in marked increases in the rate of growth. To reap the financial benefits of the faster growth, plantation managers are more and more inclined to reduce rotation ages, which inevitably results in the production of higher proportions of juvenile wood at final harvest, and lumber which often does not meet the minimum requirements for stiffness for structural lumber. Knowledge of the variation and the accurate prediction of the mechanical properties of the timber of standing trees can have various benefits for growers and processors of trees. It can be used for tree allocation to different processing facilities, for processing production planning, and to assist tree breeders to screen and select for superior breeding material. The objectives of this study were (1), to examine the within‐ and between‐tree variation in wood properties of young South African grown Pinus patula trees known to have important impacts on the suitability of sawn lumber for structural purposes and (2), to develop empirical prediction models for the flexural lumber properties from standing Pinus patula, based on variables that could be assessed non‐destructively from standing trees. Sample material was obtained from 170 trees (16‐20 years old) established in 17 compartments along the Mpumalanga escarpment of South Africa. A large number of variables which could be obtained non‐destructively from the trees while they were still standing, were measured. The trees were subsequently felled and two logs, 2.1 m in length, were extracted from each tree at two height positions. The 340 logs were processed into 1402 pieces of lumber for further measurements and destructive testing. Results showed that the mean modulus of elasticity measured on edge (MOEedge) was far below the limits set for structural grade softwood timber in South Africa. All the desirable properties for structural lumber improved with distance from the pith with the exception of the 5th percentile value for modulus of rupture (MOR), which was higher at the pith than for the boards processed adjacent to the pith. Boards processed from the lower part of the stem were superior in most of the important properties compared to those higher up in the stem. Separate multiple regression models for predicting the average dynamic MOE (MOEdyn) of individual boards, trees and compartments were developed. The models managed to explain 68%, 60% and 95% of the variation in MOEdyn respectively. The models developed for MOR explained 40% and 42% of variability at board and tree level respectively. At compartment level, 80% of the variation in the 5th percentile MOR value could be explained by the model. Sensitivity analyses showed that site index at base age of 10 years, acoustic time‐of‐flight, wood density and ring width were the most influential variables in the MOE models. The models indicated that tree slenderness during early growth seems to play a major role in determining the dynamic MOE and MOR of lumber. This is in agreement with Euler’s buckling theory and the bending stress theory. Microfibril angle (MFA) and density were measured on radial strips taken from a sub‐sample of trees with the Silviscan 3 technology. The mean microfibril angle per year ring in Pinus patula varied between 7o and 29o. In general MFA decreased with distance from the pith and height above ground level. A multiple regression model including microfibril angle, density and ring width explained 71% of the variation in the dynamic MOE of boards. Sensitivity analysis on the model showed that microfibril angle and density had roughly equal influences on predicting the MOEdyn of Pinus patula boards.
AFRIKAANSE OPSOMMING: Pinus patula is die mees aangeplante naaldhoutspesie in die tropiese en sub‐tropiese areas van die wêreld. Dit is die grootste bron van saagblokke vir die produksie van strukturele hout in SA. Intensiewe boskultuurpraktyke en boomteling het gelei tot ‘n merkbare verhoging in die groeitempo van die spesie. Plantasiebestuurders is gevolglik geneig om rotasie‐ouderdomme te verlaag, wat lei tot ‘n groter persentasie jeughout wat nie aan die minimum styfheidvereistes van strukturele hout voldoen nie. Kennis van die variasie en die akkurate voorspelling van die meganiese eienskappe van staande bome kan voordele inhou vir beide die verbouers en verwerkers van bome. Dit kan byvoorbeeld van hulp wees met die toewysing van bome aan verwerkingsfasiliteite, vir produksiebeplanning, en vir ondersteuning met die keuse van teelmateriaal vir boomtelers. Die doelwitte van hierdie studie was (1), om die binne– en tussenboomvariasie in die houteienskappe, wat ‘n bepalende invloed het op die geskiktheid van jong Suid Afrikaanse Pinus patula bome vir strukturele hout produksie, te ondersoek en (2), om empiriese modelle vir die voorspelling van die buigeienskappe van planke te ontwikkel, gebaseer op veranderlikes wat niedestruktief op staande Pinus patula bome ge‐evalueer is. Monsters vir die studie is verkry vanaf 170 bome (16‐20 jaar oud), geplant in 17 vakke op die Mpumalanga platorand van Suid Afrika. ‘n Groot aantal veranderlikes is nie‐destruktief gemeet op die staande bome waarna die bome gevel is en twee saagblokke, 2.1m in lengte, is op twee hoogte posisies uit elke boom verwyder. Die 340 blokke is verwerk tot 1402 planke vir verdere metings en destruktiewe toetse. Resultate het getoon dat die gemiddelde modulus van elastisiteit gemeet op die dwarskant (MOEedge) aansienlik laer was as wat vereis word vir strukturelegraad hout in Suid Afrika. Al die gewenste eienskappe het toegeneem met afstand vanaf die murg behalwe die 5de persentiel breekmodulus (MOR), wat hoër was vir murgplanke as vir aangrensende planke. Planke afkomstig van die laer dele van die stam het oor die algemeen beter eienskappe gehad as planke afkomstig van die hoër dele. Veelvuldige regressiemodelle kon 68%, 60% en 95% van die variasie in die gemiddelde dinamiese MOE (MOEdyn) op die vlak van onderskeidelik individuele planke, bome en vakke verklaar. Die modelle vir MOR kon 40% en 42% van die variasie op onderskeidelik plank‐ en boomvlak verklaar. Die model vir 5de persentiel MOR van vakke kon 80% van die variasie verklaar. ‘n Sensitiwiteitsanalise het aangetoon dat groeiplekindeks op ouderdom 10, akoestiese vlugtyd, digtheid en jaarringwydte die belangrikste veranderlikes was wat MOEdyn beïnvloed het. Die modelle het aangetoon dat die slankheid van bome tydens vroeë groei vermoedelik ‘n belangrike invloed op die MOEdyn en MOR van planke het. Dit is in ooreenstemming met Euler se knikteorie en die buigsterkteteorie. Die mikrofibrilhoek en digtheid van ‘n steekproef van die bome is gemeet met die Silviscan 3 apparaat. Die gemiddelde mikrofibrilhoek per jaarring het tussen 7 o en 29o varieer. Hierdie variasie was hoofsaaklik afhanklik van boomhoogte en aantal jaarringe vanaf die murg. ‘n Veelvuldige regressiemodel wat mikrofibrilhoek, digtheid en jaarringwydte insluit, kon 71% van die variasie in MOEdyn verklaar. ‘n Sensitiwiteitsanalise op die model het aangetoon dat mikrofibrilhoek en digtheid ongeveer ewe belangrik was wat betref hulle invloed op die voorspelde MOEdyn van Pinus patula planke.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2009.
jfl2010
ENGLISH ABSTRACT: The past forest management strategies in Zambia did not allow participation of local communities in the management of Forest Reserves and sharing of benefits. The Zambia forest sector was reviewed between 1987 and 1997 culminating into the National Forestry Policy of 1998 and Forests Act of 1999, which provided for joint or participatory forestry management and share of derived benefits. In 2000, the Forestry Department initiated a pilot project to develop and implement JFM. This study was conducted in Dambwa JFM area in Livingstone to evaluate local people’s participation in JFM; perceptions on the effect of JFM on local livelihoods; and the impact of JFM on forest condition. The study was conducted through the use of household questionnaires, interviews with key informants, focus group discussions, field observation, and vegetation assessment. The results showed that more than half (68%) of the respondents were aware of JFM and almost the same number (64%) participated in JFM project. Participation of men in JFM activities was higher than women, although more women attended meetings than men. The results further showed that local management structures existed at district, forest area and village levels for coordination of JFM activities. Forest User Groups (FUGs) were also established in the area. The prominent FUG was the Mungongo oil pressing and was the only FUG functional at the time of the study. Forest Management Committee, Village Resources Management Committee and FUG members were found to be more involved in JFM activities than other members of the local community. Only a small number (8%) of local people reported improvement in household socio-economic conditions after the introduction of JFM, while the majority (79%) perceived the Forestry Department to be the major beneficiary in the JFM. The study revealed that there was a loss of enthusiasm in JFM among local people largely due to the absence of economic benefits and limited decision-making powers. However, the relationship between local people and Forestry Department was reported to have improved. The overall forest stocking was found to be low (219 SPH) with nearly all (90%) of the stems below 30 cm DBH, including the selected valuable tree species of Baikiaea plurijuga, Pterocarpus angolensis, Guibourtia coleosperma, Afzelia quanzensis and Colophospermum mopane. This implies that the forest area was previously overexploited rendering it uneconomical for commercial exploitation to provide benefits to local people on sustainable basis. However, the results showed a lot of saplings (10,000 SPH) in the Forest Reserve signifying adequate regeneration, including that of the valuable species, except for Afzelia quanzensis and Guibourtia coleosperma. The abundant natural regeneration implies that there was adequate forest protection and management following the introduction of JFM, which enhances regeneration. It is recommended that the Forestry Department should continue with public awareness on JFM to increase understanding and stakeholders’ involvement. The Forests Act of 1999 should be commenced and amended to support full implementation of JFM. The value of the forest also needs to be enhanced to increase benefit for local people and long-term conservation.

Thesis (MScFor) -- Stellenbosch University, 2003.
ENGLISH ABSTRACT: Fire is a threat to all forest plantations. As a result, growers are forced to take active measures to reduce the incidence and extent of fires in their plantations. This thesis is an attempt to collate 846 fire records for eight Komatiland Forests (KLF) plantations in Mpumalanga North for the period 1950 to 1999. Up to now, these reports and the information therein, were not utilised by KLF for planning or for evaluating fire management practices. The only other studies in South Africa, using similar data, were conducted by LeRoux (1988) and Kromhout (1990). A brief background of the forestry industry in South Africa, and in particular Mpumalanga is presented. The main text of the report covers a presentation on fire causes, extent of damage (both in area and in Rand value) and various aspects related to time of ignition and response times. A detailed analysis was done to identify possible relationships between the variables related to compartment, climate and different fire suppression activities. A cause and frequency prediction model was developed that will assist fi re managers in identifying and determining probabilities of fires per cause. Statistical guidelines regarding the planning of fire management around fires caused by honey hunters, lightning, work-related factors, and the activities of people (public, own labour, contractors) are presented. Conclusions were drawn from the results of the analyses of the fire data, which covered a period of 47 years. Recommendations regarding guidelines for strategic fi re management for the Mpumalanga North plantations were made. The main conclusions are: • Statistics on previous fires are very useful in fire management planning as it supplies valuable information on fire causes, time of ignition , past performance related to response times, fire fighting times and damaged caused. • • • • The average area lost due to fires in the study area is 209.9 ha or 0.43% of the plantation area per annum. People-related fires (arson, smokers, picnickers, children and neighbours) caused most of the wild fires (48%), followed by lightning (22%). Some plantations performed poorly, with the occurrence of up to double the number of fires per 1 000 ha of plantation compared to other plantations in the same geographic area. There are definite patterns in the frequency of fires per cause with month of the year. These patterns are valuable for the development of strategies to manage fires caused by honey hunters, lightning fires and work-related fires.
AFRIKAANSE OPSOMMING: Brande is 'n bedreiging vir aile bosbou plantasies. Dit is dus noodsaaklik dat kwekers maatreeHs tref om die voorkoms en omvang van brande in plantasies te beperk. Hierdie tesis poog om 846 vuurverslae se inligting te ontleed ten opsigte van agt Komatiland Forests (KLF) plantasies in Mpumalanga Noord vir die tydperk 1950 tot 1999. Tot op hede is min van die inligting wat in die verslae vervat is deur KLF vir beplanning- en evalueringsdoeleindes ten opsigte van brandbestuur gebruik. Die enigste soortgelyke studies wat op brandverslagdata in Suid-Afrika gedoen is, is gedoen deur Le Roux (1988) en Kromhout (1990). 'n Kort agtergrond oor die bosbouindustrie in Suid-Afrika en spesifiek Mpumalanga word gegee. Die tesis gee 'n oorsig oor brandoorsake, skade wat deur brande veroorsaak word (oppervlakte sowel as finansieHe waarde) en verskeie aspekte rakende brandbestuur soos tyd van ontstaan en reaksietye. Data is volledig ontleed om moontlike verwantskappe te probeer vind tussen vak-, klimaat- en brandbestuursveranderlikes. 'n Oorsaak- en frekwensievoorspellingsmodel is ontwikkel wat brandbestuurders sal help om waarskynlikhede van brande per oorsaak te identifiseer. Statistiese riglyne ten opsigte van bestuursbeplanning vir weerligvure, brande deur heuninguithalers, brande as gevolg van plantasiewerksaamhede en ook brande deur mense (publiek, eie arbeid en kontrakteurs) is daargestel. Brandrekords wat oor 'n periode van 47 jaar gestrek het, is ontleed. Afleidings wat uit die resultate gemaak is, kan benut word om riglyne daar te stel vir strategiese brandbestuur in Mpumalanga Noord plantasies. Die hoof gevolgtrekkings is: • Statistiek van vorige vure is baie nuttig in brandbestuursbeplanning aangesien dit waardevolle inligting verskaf oor brand oorsake, tyd van ontstaan, historiese werkverrigting rakende reaksietye en blustye, sowel as skade wat veroorsaak is. Die gemiddelde oppervlakte beskadig in die studie area is 209.9 ha, of 0.43% van die plantasie oppervlakte per jaar. Menslike aktiwiteite (brandstigting, rakers, piekniekvure, kinders en vure van bure) het die meeste brande veroorsaak (48%), gevolg deur weerlig (22%). Sommige plantasies het swak gevaar en het tot soveel as dubbel die aantal vure per 1 000 ha plantasie gehad in vergelyking met ander plantasies in dieselfde geografiese gebied. Daar is duidelike patrone gevind in die frekwensie van brande per oorsaak oor maande van die jaar. Hierdie patrone is nuttig vir die ontwikkeling van bestuurstrategie vir brande wat veroorsaak word deur heuningversamelaars, weerlig en werkverwante aktiwiteite (plantasieaktiwiteite).

Assignment (MFor)--Stellenbosch University, 2001.
ENGLISH ABSTRACT: The ongoing environmental destruction that results from the continuous use of the woodland resources for economic purposes has caused extensive changes in the original vegetation of Goba area of southern Mozambique. Developing alternative sources of income for communities can reduce their dependence on the production of charcoal, building materials and wood carvings. The lack of infrastructure and remoteness of these localities from the markets make alternatives economically unfeasible and thus unsustainable for rural development. Ineffective policy planning that does not address the problem in a holistic way causes the dilemma of local people in remote areas. The challenge at Goba is to develop alternative livelihoods that are economically, socially and ecologically sustainable. Nature-based tourism has been identified as such an alternative to realize this goal. However, this development requires incentives for sustainable resource use, which can be created either by expanding the benefits accruing from the efficient use of the resource or by changing the distribution of the benefits and cost in favor of the users. In many cases, local communities have developed tourism initiatives in ecologically fragile, remote areas, without sound planning based on detailed ecological and socio-economic information. Uncontrolled flows of tourists in unplanned tourist destinations degrade these areas. These destinations lose their aesthetic appeal; tourism flow decreases and consequently new attractions are opened. This study is of a land use planning nature and follows a combination of existing framework tools. The primary aim of this study was to develop simple guidelines for nature-based tourism that contribute to the conservation and management of the rural woodland areas as well as to the improved socio-economic welfare of rural communities in the Goba area. The study used baseline information for planning, focusing on the tourism market and on the ecological and socia-economical aspects of the siudy area. Two strategies were used to obtain the information, namely market research and attraction resources analysis. The market research in the southern part of Mozambique shows that: International tourist flows are at present from Southern African countries mostly South Africa (more than 50%), North America, Europe and Australia or Asia. Mozambique is perceived mainly as a sunny beach destination for vacations and weekends though most of the tourists were engaged in multi-destination itineraries that included safari, wildernesses, bird watching, touring and curiosity. There was no evidence from any tourist that nature tourism was the reason to visit Mozambique, but many of them said that they would visit ecotourism and nature tourism destinations if available. The average daily expenditure per tourist was found to be US$47. Tourists from long-haul distances had higher disposable expenditures and stayed longer in both attraction assets and in the country. Sixty nine per cent (69%) of surveyed tourists were over 50 years of age and they were mostly males (57%). The results show clearly that many issues must be taken into consideration where the development of ecotourism and nature-based tourism, especially in rural areas, is concerned. Such considerations should include (i) careful planning of the destinations based on the local developmental policy; (ii) developing saleable tourist products and packages and (iii), promotional strategies to expand the market to capture tourists with high average daily expenditure. The rural communities can then have a chance to develop nature-based tourism that uses outstanding natural resources. The resources analysis study results revealed that: The rugged topographic, climatic conditions of Goba water catchment area and the distance from settlements have naturally preserved local forest resources from human utilization. The area has well conserved and differentiated natural scenic landscape. These scenic landscapes have recreational values as well as environmental contrast, scientific discovery potential and retention of vanishing biological species. To preserve or improve the management of these landscapes, it is essential to consider recreation use in relation to all other potential values. Few existing landscapes showed a relative ability to absorb impacts produced by facility development with a minimum negative effect on the visual and ecological quality of the landscape. The majority of the landscapes have some potential for primitive and sensitive recreational spectrum. All these results are consistent with results from similar studies on watershed and water catchment ecology. Given the constraints on the environmental settings of the Goba landscapes, it is recommended that the basic and logic framework development should attract tourists interested in the more primitive portion of the recreational spectrum and should have fewer facilities of small-scale building. These facilities should be rustic in character with less service and more emphasis on self-reliance. Improved management of the Goba ecosystem is needed to maintain the ecological functions of the catchment and local culture and rurality. In conclusion, this study suggests that, if on these remote fragile ecosystems local communities can protect and market attractive quality-of-life-amenities, maintain a relatively low cost of living, and offer serviceable links to global telecommunication infrastructures in order to attract tourists and retirees, these communities can survive and may even thrive as local economies. An incentive planning method and sustained extension outreach effort in rural development, which focuses on nourishing local action at the grassroots level, will complement such a policy strategy.
AFRIKAANSE OPSOMMING: Omvattende verandering van die natuurlike plantegroei in die Goba area van suiderlike Mosambiek is teweeg gebring deur die deurlopende bentting van die omgewing deur die misbruik van die natuurlike hulpbronne vir ekonomiese wins. Die ontwikkeling van alternatiewe inkomstebronne vir plaaslike gemeenskap kan hul afhanklikheid van hout vir die produksie van houtskool, boumateriaal en houtsneewerk verminder. Die gebrek aan infrastruktuur en die groot afstande na markte maak die verkoop van die houtprodukte in stedelike gebiede onprakties en dus nie 'n volhoubare oplossing vir landelike ontwikkeling nie. Oneffektiewe beleidsbeplanning wat die probleem nie holisites benader nie veroorsaak 'n dilemma vir inwoners in afgeleë gebiede. Die uitdaging in Goba is om alternatiewe bronne van inkomste te ontwikkel wat ekonomies, sosiaal en ekologies volhoubaar is. Natuurgebaseerde toerisme is geïdentifiseer as 'n moontlike alternatief wat aan die doel kan beantwoord. Die ontwikkeling van eko-toerisme sal egter net slaag indien die plaaslike bevolking genoegsaam aangemoedig word om die natuurlike hulpbronne op 'n volhoubare basis te benut. Dit kan gedoen word óf deur winste terug te ploeg in die omgewing en so die toerisme basis te vergroot óf deur winsdeling op 'n gebruikersgunstige voordele- en kostebasis te behartig. In baie gevalle het plaaslike gemeenskappe toerisme inisiatiewe in sensitiewe, afgeleë gebiede ontwikkel, sonder deeglike beplanning wat op uitgebreide ekologiese en sosio-ekonomiese inligting berus. Die onbeheerde toeriste aanloop na onbeplande areas lei tot die stelselmatige vernietiging daarvan. Hierdie bestemmings verloor hul estetiese waarde en het tot gevolg dat toeriste ander ongerepte areas gaan soek. Hierdie studie handeloor die beplanning van grondgebruik en volg 'n kombinasie van bestaande raamwerk prosedure. Die primêre doel van hierdie ondersoek is om eenvoudige riglyne vir natuurgebaseede eko-toerisme te ontwikkel wat 'n bydra kan lewer tot die bewaring en bestuur van die natuurlike wonde en wat die sosioekonomiese welvaart van die plaaslike bevolking van Goba sal bevorder. Die studie maak gebruik van basiese inligting vir beplanning, en fokus op die toeristemark sowel as op die ekologiese en sosioekonomiese aspekte van die studie-area. Die twee strategieë wat gevolg is om inligting in te win is marknavorsing en die analise van toeriste-attraksie hulpbronne. Marknavorsing in die suide van Mosambiek toon dat die meerderheid internasionale besoekers aan Mosambiek afkomstig is van lande in Suidelike Afrika (Suid-Afrika alleen 50%), en daarna uit Noord- Amerika, Europa and Australië/Asië. Mosambiek word hoofsaaklik as 'n sonnige strandoord-bestemming vir vakansies en naweke beskou, hoewel die meeste toeriste 'n multi-bestemming reisplan volg wat safaris, ornitologie, reis en besoeke aan besienswaardighede insluit. Daar is geen bewys gevind dat enige toeris Mosambiek besoek het met eko-toerisme as doel nie, maar baie sou belangstelom dit te doen indien ekoen natuurgebaseerde toeriste-betemmings beskikbaar was. Die gemiddelde daaglikse uitgawe per toeris was US$47. Toeriste wat groot afstande moes aflê om hul bestemming te bereik het meer beskikbare fondse en bly langer, beide in die land en by verskillende attraksies. Van die toeriste by wie die opname gemaak is 69% ouer as 50 jaar en die meerderheid (57%) was mans. Die resultate toon dat daar talle faktore is om in ag te neem by die ontwikkeling van 'n landelike area vir natuurgebaseede en eko-toerisme. Daar moet aandag gegee word aan (i) deeglike beplanning van die bestemming gebaseer op die plaaslike ontwikkelingsbeleid; (ii) die ontwikkeling van verkoopbare toeriste produkte en pakkette;en (iii), promosie strategieë om die mark uit te brei om toeriste wat meer spandeer te lok. Die landelike gemeenskappe word sodoende die geleentheid gebied om hul besondere natuurlike hulpbronne te ontwikkel vir natuurgebaseerde toerisme. Die hulpbron-analise toon dat die afgeleë en bergagtige topografie en die klimaatsomstandighede van Goba se wateropvangsgebied as natuurlike beskerming vir inheense woude teen die benutting deur die plaaslike bevolking gedien het. Die area is goed bewaar met skouspelagtige natuurtonele. Die skouspelagtige landskap beskik oor rekreasiewaarde sowel as omgewingskontras, potensiaal vir wetenskaplike ontdekkings en vir bewaring van seldsame fauna en flora. Om hierdie landskap te bewaar of die bestuur daarvan te verbeter, moet gebruik vir rekreasie in verhouding tot die ander potensiële waardes beskou word. Daar is beperkte areas wat die vermoë besit om ontwikkeling te absorbeer en waar die verbouing van fasiliteite slegs 'n minimale negatiewe effek op die visuele en ekologiese kwaliteit sal hê. Die potensiaal bestaan egter vir alle areas om op 'n beperkte skaalontwikkel te word vir die primitiewe en sensitiewe sektor van die rekreasie spektrum. Die resultate van die vavorsing stem ooreen met soortgelyke studies van waterskeiding- en wateropvangsgebied-ekologie en ontwikkeling. Vir die gegewe omgewingsbeperkings van Goba word dit aanbeveel dat ontwikkeling op 'n basiese vlak geskied om daadie proporsie van die toeriste te lok wat in die sogenaamde wildernis-ervaring belangstel. Geboue en beperkte fasiliteite moet slegs op klein skaal opgerig word. Die fasiliteite moet by die omgewing inpas en die klem moet op selfvoorsiening eerder as op dienstelewering val. Die bestuur van die Goba ekosisteem moet egter verbeter om die ekologiese funksie en die plaaslike kultuur en landelikeid te behou. Die bevinding van die studie is dat indien ver-afgeleë en sensitiewe ekosisteme deur die plaaslike bevolking bestuur en beskerm word, dit tot ekonomiese welvaart van die landelike gebiede kan lei. Hierdie areas moet bestuur word sodat die landelike karakter as toeriste aantreklikheid behou word, dat die lewenskoste relatief laag bly en dat verbindings met die buitewêreld op telekommunikasie vlak ingestel word. Beplanning moet op 'n aansporingsbasis gegrond wees met uitreikingsprogramme met landelike ontwikkeling as doel. Aanmoediging van plaaslike aksie op grondvlak behoort so 'n beleidstrategie te versterk.

Thesis (MScFor (Forest and Wood Science))--Stellenbosch University, 2008.
The characterization of soils in Nzara District of Southern Sudan in comparison to other tropical teak growing countries (Tectona grandis) – in respect of extensions to existing and/or the establishment of new teak plantations – were done by firstly considering the soils of three existing plantations: Yoboa, Mabarizinga and Nagondi, and secondly by considering soils outside and inside the existing teak plantations in respect of land uses. From these soil characterizations, it emerged that considerable positive returns can be expected from teak plantings in the area as an investment, provided that appropriate site management is implemented. Climatic data of the Nzara area compared favorably with the climatic range of areas where teak grows naturally and the world’s dominant producers: mean annual rainfall 1350-1600 mm with a distribution over 6-8 months compares well with that of Myanmar (1250-3750 mm) and Indonesia (1511-2108 mm) both with at least 3 months of dry season. The mean annual temperature of 28-350C compares well with 15-410C and 30-320C of Myanmar and Indonesia respectively. The Yoboa and Mabarizinga sites should be prioritized as they appear slightly more suitable than the Nagondi site. All three sites have a dominant soil texture of Sandy Clay Loam similar to Sandy Loam of most areas of other tropical countries where teak is growing well (such as India, Indonesia and Nigeria). Yoboa and Mabarizinga however distinguish themselves by having the highest soil pHwater values range from 6.4±0.56 and 6.04±0.7 in top soils; 5.91±0.5 and 5.46±0.61 in subsoils at Yoboa and Mabarizinga respectively; the highest soil organic matter content 1.8±0.34% and 1.92±0.43% in topsoil 0.89±0.16% and 1.13±0.19% in subsoils; as well as the highest P content in both available (0.09±0.04% and 0.03±0.04% for topsoils) and total forms (1.19±0.26% and 0.9±0.3% also on topsoils). These values though very low in absolute terms, are not much different from those of other tropical teak-growing countries. Management strategies intended to preserve and improve the present status, particularly the protection of top soil horizons against mainly water erosion, would be able to boost the site productivity.

Thesis (MFor ) -- University of Stellenbosch, 2003.
ENGLISH ABSTRACT: The bulk of paper grades destined for the printing industry are produced on modern paper machines which continuously become wider and faster. In order to improve printability, print quality and dimensional stability, such papers contain a large percentage of mineral pigments either in the form of internal loading or external coatings. Although mineral pigments exercise a substantial beneficial effect on paper surface quality, unfortunately these minerals do not contribute towards sheet strength and machine runnability. Today's papermakers are faced with the dilemma of producing highly filled and coated printing papers with low grammages on faster running paper machines, but often lacking the required quality of fibre resources to secure a smooth runnability of such at high speeds. Standard fibre furnishes will have to be upgraded with special types of reinforcing fibres in order to meet the demands of sheet strength and machine runnability. The investigation had succeeded to identify a new suitable fibre resource, which would satisfy the demand of a reinforcing type natural material.
AFRIKAANSE OPSOMMING: Die oorgrootte meerderheid tipes papier wat vir die drukkersbedryf bestem is, word op moderne papiermasjiene vervaardig wat steeds breër en vinniger word. Om die drukbaarheid, drukkwaliteit en dimensionele stabiliteit te verbeter, bevat sulke papiere groot hoeveelhede minerale pigmente wat in die vorm van interne ladings of as eksterne bestrykings teenwoordig is. Alhoewel minerale pigmente -n merkbare voordelige effek op die papier oppervlakte-kwaliteit uittoefen, dra sulke pigmente ongelukkig nie by tot die sterkte en loopvermoë van die papier nie. Die hedendaagse papiervervaardiger word konfronteer met die dilemma om swaar gevuldeen bestrykte drukpapiere met lae oppervlaktegewig op vinniger lopende papiermasjiene te vervaardig. Dit gebeur dikwels sonder die beskikbaarheid van die nodige hoëkwaliteit veselbronne om te verseker dat die loopvermoë van die papier teen hoë spoed nie benadeel word nie. Standaard veselsamestellings salopgegradeer moet word met spesiale tipe versterkingsvesels om aan die uitdaging van hoë velsterkte en masjien-Ioopvermoë te voldoen. Hierdie ondersoek het daarin geslaag om 'n nuwe geskikte veselbron te dentifiseer en wat aandie behoeftes van 'n versterkingsvesel sal voldoen.

Thesis (PhD (Forest and Wood Science))--Stellenbosch University, 2007.
ENGLISH ABSTRACT: There has been a reported reduction in the durability of creosote treated, wooden utility poles in South Africa in recent years. Several factors could have been responsible for this. In this study, Eucalyptus grandis pole drying schedules currently used, methods of measurement of moisture content (MC) after drying and drying defects were investigated. Relationships involving drying defects and MC gradient before treatment which may help in the development of simple nondestructive methods of assessing defects such as surface checking, honeycomb and collapse, and MC gradient were also explored. The long term goal of this study was to increase the durability of treated poles by avoiding unacceptable drying defects and MC values before treatment. The results of this investigation are presented in the following chapters: an introduction motivating the aims of the investigations (Chapter 1); a review of literature relevant to MC and drying defects in sawn or round wood (Chapter 2); ready for press manuscripts on MC and drying defects in kiln-dried E. grandis poles (Chapters 3 to 7) and a general conclusion that links up chapters 3 to 7, and recommendations (Chapter 8). The auger drill method gave reliable MC values when samples in increments of 25 mm depths into the pole were taken. However, when single samples of 50 mm and 75 mm depths were considered, the auger drill MC measurements were unreliable. It was concluded that SABS SM 983 (2000), which specifies taking single radial auger drill samples of depth 70±5 mm at pole mid length, is not a reliable method of measuring MC in a kiln-dried E. grandis pole. Correlation results indicated that tree growth factors such as sapwood depth, green MC and heartwood percentage were related to final drying defects and may be used as criteria for pole sorting before kiln drying. Also, the number of valleys per unit length (VPUL) of the circumference at the theoretical ground line (TGL) was positively correlated with honeycomb and closed surface checks, implying that VPUL as a parameter of the pole circumference profile can be used to assess invisible, internal defects. The dry bulb temperature (Tdb) of 80oC, used to dry poles in industry, was too high and resulted into unacceptable levels of drying defects in kiln dried E. grandis poles. In addition, the drying period of 8 days was too short to attain an acceptable MC gradient in poles. It is, therefore, recommended that: To use the auger drill method to reliably determine the moisture content of a pole, samples in increments of 25 mm should be taken. MC measurements should be made at the most critical zones of a pole such as the TGL and not higher up since there is normally considerable MC variation in the longitudinal direction. It is also important to consider sampling more than one position on the pole circumference to cater for the MC variation in the tangential direction. For poles with large sapwood depths i.e. >15mm, mild drying conditions at the beginning of a drying run should be used, since such poles may be more susceptible to surface checking. Poles with large heartwood percentages should also be dried with suitable kiln schedules, i.e. with low Tdb to minimise honeycomb and collapse. In general, Tdb lower than 80oC should be considered in order to reduce the defects to acceptable levels. Poles should be dried for longer than 8 days even at Tdb as high as 80oC to reduce the MC to acceptable values and gradients. Since only three schedules were tested, more drying schedules should be investigated to make reliable conclusions about the effect of schedule on drying defects. In addition, more poles per schedule should be considered in order to obtain statistically reliable results. The relationship of pole diameter and drying defects also requires further investigation. Since a limited sample was used to test for the effect of source of poles and drying schedules on defect correlations, further studies should be done on sufficient samples to come up with more reliable conclusions. It is also necessary to further investigate the possible variation in correlation of VPUL and internal defects on a large sample of poles from specific sources and drying schedules.
AFRIKAANSE OPSOMMING: Die afgelope paar jaar is waargeneem dat kreosootbehandelde transmissiepale 'n afname in duursaamheid toon. Verskeie faktore kan hiervoor verantwoordelik wees. In hierdie studie is huidige Eucalyptus grandis oonddrogingskedules en voggehalte- (VG) bepalingsmetodes vóór en na droging asook drogingsdefekte ondersoek. Verwantskappe tussen drogingsdefekte en VG-gradiënt vóór behandeling wat kan meehelp om nie-destruktiewe metodes te ontwikkel om defekte soos oppervlaktekrake, interne barste en instorting en VG-gradiënt te bepaal, is ook bestudeer. Die langtermyn doelwit van hierdie studie is om die duursaamheid van behandelde pale te verbeter deur onaanvaarbare drogingsdefekte en voggehaltes vóór behandeling te vermy. Die resultate van hierdie ondersoek word in die volgende hoofstukke bespreek: 'n inleiding waarin die doelwitte van die onderskeie ondersoeke motiveer word (Hoofstuk 1); 'n oorsig van die literatuur relevant tot VG en drogingsdefekte in gesaagde en rondehout (Hoofstuk 2); persklaar manuskripte oor VG en drogingsdefekte in oondgedroogde E. grandis pale (Hoofstukke 3 tot 7) en 'n algemene gevolgtrekking wat bevindings uit hoofstukke 3 tot 7 saamvat gevolg deur aanbevelings (Hoofstuk 8). Die augerboor-metode kon betroubare VG-waardes lewer indien monsters van 25mm diepteinkremente in die paal geneem is. Augerboor-voggehaltemetings met enkel 50mm en 75mm monsters was egter onbetroubaar. Daar is bevind dat SABS SM 983 (2000), wat 'n enkel radiale augerboormonster tot op 'n diepte van 70±5 mm in die middel van die lengte van die paal spesifiseer, nie 'n betroubare VG-bepalingsmetode vir oondgedroogde E. grandis pale is nie. Die resultate het aangetoon dat boomgroeifaktore soos spinthoutdiepte, groen voggehalte en die persentasie kernhout aan drogingsdefekte verwant is en as basis vir sortering van pale vóór oonddroging gebruik kan word. Ook kon die aantal valleie per eenheidslengte (e. VPUL) van die omtrek by die teoretiese grondlyn (TGL) positief met interne barste en geslote oppervlaktekrake korreleer word wat impliseer dat VPUL as parameter van die omtrekprofiel van die paal gebruik kan word om onsigbare, interne defekte mee vas te stel. Die droëbaltemperatuur (Tdb) van 80oC wat in die industrie gebruik word, was te hoog omdat dit onaanvaarbare vlakke van drogingsdefekte in oondgedroogde E. grandis veroorsaak het. Daarbenewens was die drogingsperiode van 8 dae by 'n Tdb van 80oC te kort om 'n aanvaarbare VG-gradiënt te lewer. Die volgende word derhalwe aanbeveel: Om betroubare VG-resultate d.m.v. die augerboormetode te verkry, behoort monsters in inkremente van 25mm geneem te word. VG-metings behoort in die mees kritiese dele van 'n paal gedoen te word byv. by TGL en nie hoër nie omdat daar normaalweg beduidende VG-variasie in die longitudinale rigting is. Dis ook belangrik om op meer as een posisie op die omtrek te meet om vir die variasie in die tangensiale rigting voorsiening te maak. Ligte drogingstoestande behoort aan die begin van die drogingsproses by pale met groot spinthoutdieptes, bv. > 15mm, gebruik te word omdat sulke pale meer geneigd tot oppervlaktekrake is. Pale met hoë kernhoutpersentasies moet ook met geskikte drogingskedules, bv. met lae Tdb, gedroog word om interne barste en ineenstorting te verminder. Oor die algemeen behoort Tdb laer as 80oC oorweeg te word om die omvang van defekte by aanvaarbare vlakke te hou. Selfs by Tdb so hoog as 80oC behoort pale langer as 8 dae te droog om die VG tot by aanvaarbare waardes en 'n gradiënt te bring. Omdat slegs drie skedules evalueer is, behoort meer skedules ondersoek word om betroubare gevolgtrekkings oor die effek van skedule op drogingsdefekte te verskaf. Addisioneel behoort meer pale per skedule oorweeg word om statisties betroubare resultate te verkry. Die verwantskap tussen paaldeursnee en drogingsdefekte benodig ook verdere ondersoek. Aangesien 'n beperkte aantal pale gebruik is om die herkoms en drogingskedule met defekte te korreleer, behoort verdere studie op genoeg pale gedoen te word om meer betroubare gevolgtrekkings te kry. Dit is ook noodsaaklik om die moontlike variasie in die korrelasie tussen VPUL en interne defekte op 'n groot aantal pale van spesifieke herkoms en drogingskedules vas te stel.

The establishment of plantation forests in areas not viable for agriculture can make a significant contribution to the economy. The yield from 1 ha of plantation forest depends on the management purpose - obtaining of round wood (pulpwood, sawnlog, veneer log, tare), bioenergy and extraction of tree foliage (broadleaved and coniferous). In Latvia, based on 2019 data, plantation forests achieve 2760 ha of Scots pine, 7855 ha of Norway spruce, 7431 ha of Birch, 2123 ha of Grey alder, 1274 ha of Black alder and Populus spp. and 618 ha of Salix spp. Estimated and projected gains are calculated both as round wood over 20 to 50 years: pine - 410-to 994 thou. m3; spruce, - 335 to 2.906 thou. m3, birch - 1.040 -2.452 thou. m3. Accordingly, it is possible to obtain gross income from the whole plantation forest area in Latvia: pine-12.42-63.8 mln. EUR; spruce - 40.1 -192.3 mln. EUR; for birch - 32.2 -202.7 mln. Eur. Additionally to that, 18.6 -21.6 t ha-1 and 24.0 -37.0 t ha-1 of processed foliage can be obtained from 1 ha of pine and spruce forest plantations (40-50 years old). Alnus incana sp. (5-20 years), yielding 19.65-122.65 thou. Solid m3 and Salix spp. (3-5 years), yielding 58.71-84.97 thou. solid m3, are used for energy production, furthermore Alnus spp. wood can be used than valuable raw material for plywood production. At the same time, it is possible to capture 106-1477 thou. tonnes of CO2 equivalent. Systematic investigations of chemical composition of above mentioned Latvian plantation trees, wood and bark, have shown that incorporation of extraction treatment in existing processing schemes will allow to manufacture high value added monomeric and oligomeric products which are of great demand for substitution of synthetic ones in different economy sectors (agriculture, including means for plant protection, food industry, polymer production, pharmacy etc.). Creation of small and medium-sized enterprises in rural region in close proximity to plantations opens the opportunity for the appearance of new working places, including organization of new nurseries, plantation services, private businesses for processing of various lignocellulosic waste into new special products / semi-products / feedstock for green industrial materials and chemicals, at the same time diminishing the logistics expenses.

Global warming is one of the most important topics in power generation field. Wood pellet is carbon neutral fuel and it is expected to reduce CO2 emission from fossil fuel. Recently in Japan, wood pellet is already utilized in many pulverized coal fired boilers in a limited range of a few percent. For the further CO2 emission reduction, high co-firing ratio of wood pellet is expected. The firing system of wood pellet is required to be separated from the coal firing system in the view point of technique, and it is desired to slightly modify the existing coal firing system from the view point of dissemination. IHI developed a wood pellet mill which equipped some devices to the coal mill. By modifying one coal mill in a commercial power plant to the pellet mill, grinding wood pellet was succeeded, and co-firing rate of 25 % was achieved. This paper shows the economic and technical evaluations of wood pellet utilization in coal fired power plant including the impact of lumbering to the forest.

Enhanced forest growth may respond to demand of woody resources and contribute to the climate change mitigation. Forest soil treatment with fertilizers, as well as drainage and thinning enhance forest growth. The analysis of needles is an established method in forest science to identify the nutrient status in the forest stand and need for forest soil enrichment with fertilizers. The aim of this research is to estimate the efficiency of forest soil enrichment with wood ash and ammonium nitrate in order to eliminate nutrient deficiency in forest stands. Forest soil was enriched with wood ash fertilizer or ammonium nitrate in 2016–2017. The current year needles were collected from fertilized and control plots, from three trees in each plot. The samples were collected in the period 2018–2019. Total nitrogen (g kg-1), calcium (g kg-1), magnesium (g kg-1), and potassium (g kg-1) were analyzed in the collected samples. The chemical properties of collected needles were compared at the individual object level to estimate the impact of fertilizer on forest stand. A statistically significant increase in the concentrations of potassium and phosphorus was detected in some plots treated with wood ash and ammonium nitrate. In addition, a correlation analysis conducted between the variables of chemical properties of needles and soil showed few significant correlations between nutrient content in needles and in soil samples.